Q.At the movies, you eat two jumbo buckets of buttered popcorn and get very sick. For years afterward, you can't stand the sight of buttered popcorn. What happened? –H. Spencer

A. You developed a "taste aversion," which is quite common and quite powerful, says psychologist Spencer A. Rathus, who had the above experience. In fact, some 30 years later he still can't eat buttered popcorn, though his taste for plain popcorn was not affected and he enjoys butter on other foods.

Psychologist John P. Dworetzky adds that he used to like pears until a couple of years ago when he bit right through a large worm in a piece of the fruit. "To this day I can't eat pears. It doesn't matter that they're canned or chopped thoroughly, so that I can tell there's nothing in them. It doesn't matter that I can look carefully and see no wormholes... I even hate writing about it."

Q.You're dreaming– or at least you think you are. Is pinching yourself a good reality check? –S. Freud

A. It's as good as any, says Deirdre Barrett of Harvard Medical School. Notice if the bite of pain comes on at the right moment and in the right degree. Other tests: 1. Speak and hear if your voice sounds like your own; 2. Read from a book, glance away, then look back and see if the words stay the same.

"Dreams rarely get the details right, so look for inconsistencies. Once you've asked the 'Am-I-dreaming?' question, you're 99 percent of the way to lucidity, realizing it's only a dream," she says.

Novice lucid dreamers often wake up the moment they become lucid, so your next challenge will be to stay in the dream, says psychologist Stephen LaBerge in Exploring the World of Lucid Dreaming. One trick is to start your dream body spinning: Since vision is often the first sense to fade, an infusion of the other senses may reinvigorate the dreaming mechanism.

"It doesn't matter whether you pirouette or spin like a top or dervish, as long as you feel your dream body in motion," says LaBerge. Remind yourself the next thing you experience will probably still be a dream. Go with it. Relish the fabulous world your mind has created.

Q. Why would anyone be concerned about communicating with people in AD 12007, and how might such a message be given anyhow? –A. Toffler

A. Scientists are trying to develop a sign for a salt mine in Carlsbad, New Mexico to say, "Don't dig here, we buried nuclear waste," reports Sally Palmer in New Scientist magazine. Computer models predict the mine will collapse within 1,000 years, sealing the chemical sludge and toxic contaminants, and should be intact for the 250,000 years until the waste becomes safe.

But government legislation mandates a 10,000-year explicit safeguarding, so the message will be carved onto eight-meter-tall monoliths.

The next consideration is the language to use since the world will doubtless be vastly different 100 centuries from now. Anthropologist David Givens says that while there's no universal symbol for danger, universal facial expressions such as fear or revulsion just might work.

"There will also be a description of the site in seven languages, plus the word danger and today's symbols for biohazards and radioactivity," says Palmer. The final design will then be road-tested in remote regions of Borneo and New Guinea where people have had no "western" contact. Of course, even though none of us will ever find out if the message hits the mark, as chief scientist Roger Nelson puts it, "we have to try."

Q. How does the embarrassment smile differ from other smiles? –G. Bush

A. It's not the classic amusement or pleasure smile, which crinkles the skin around the eyes, says Christine R. Harris in American Scientist. Embarrassment smilers not only dodge eye contact but also look away faster, before the smile's apex, and may cover the mouth with a hand. Research suggests two or three embarrassment types: faux-pax (skirt hiked up in the back after visiting a restroom), center of attention (being guest of honor at a surprise party), and sticky situation (having to remind a friend of an unpaid debt). Yet not all of us find all three equally embarrassing.

Literally, could embarrassment kill you? It might if it prevents someone from jumping into a river to save you from drowning, due to uncertain signals of what's happening and not wanting to seem a fool. Or if you're too embarrassed to get a needed colonoscopy. Less clear is whether the elevated heart rate and blood pressure of some embarrassed subjects pose a physical danger. The true shame is how little is known about this serious subject.

Q. You're in a small elevator when the guy next to you suddenly breaks the sound barrier– twice. Yow! Two sonic booms just a few feet away from you. What gives? –H.J. Heinz

A. He just coughed and sneezed loudly. Ah well, maybe the high-speed air coughed out through his trachea and upper bronchi will be just what he needs to unloose any excess mucous, says Jearl Walker in The Flying Circus of Physics. This is accomplished by breathing in a lot of air, trapping it behind a closed glottis (narrowed opening in the larynx), and increasing the pressure by contracting the lungs, partially collapsing the trachea and upper bronchi to narrow the pathway. Then the air is expelled by suddenly reopening the glottis.

The airflow quickly becomes turbulent, sending sound waves into the air and the lung tissue. At first, the vocal folds in the larynx produce no sound, held wide apart so as not to obstruct the airflow, but toward the end of the cough, they do.

"I calculate the airspeed during this explosive rush reaches or even exceeds the speed of sound, and thus a mild shock wave (or sonic boom) comes up from the throat. People with supersonic coughs or sneezes are rarely appreciated on elevators," Walker says.

Q. At the movies, you eat two jumbo buckets of buttered popcorn and get very sick. For years afterward, you can't stand the sight of buttered popcorn. What happened? –H. Spencer

A. You developed a "taste aversion," which is quite common and quite powerful, says psychologist Spencer A. Rathus, who had the above experience. In fact, some 30 years later he still can't eat buttered popcorn, though his taste for plain popcorn was not affected, and he enjoys butter on other foods.

Psychologist John P. Dworetzky adds that he used to like pears until a couple of years ago when he bit right through a large worm in a piece of the fruit.

"To this day I can't eat pears. It doesn't matter that they're canned or chopped thoroughly, so that I can tell there's nothing in them. It doesn't matter that I can look carefully and see no wormholes... I even hate writing about it."

Send Strange questions to brothers Bill and Rich at strangetrue@compuserve.com.